simple pendulum

• equipment

  • pendulum bob on 2m long string
  • stand and clamp
  • pin and blu-tack
  • meter ruler
  • stopwatch
  • two wooden blocks
• method

  • set up apparatus
  • adjust point of suspension so distance from point to centre of mass of pendulum bob is 1.5m
  • pull pendulum to side and release so it has small amplitude
  • start stopwatch when it passes fiducial marker
  • stop stopwatch after 10 complete oscillations and record time
  • divide by 10 to find time period of pendulum
  • decrease length by 0.1m and repeat reducing by 0.1m each time down to 0.5m
  • repeat experiment twice more and find meant time for each length
• graphs and calculations

  • plot graph of $T^2$ against length and draw line of best fit
  • gradient = $\frac{4\pi^2}{g}$
  • $T=$$2\pi\sqrt{\frac{L}{g}}\ \ \rightarrow\ \ T^2=$$\frac{4\pi^2}{g}L$
• safety

  • no notable risks
• improvements

  • use small pendulum bob so its easier to measure length to centre of mass
  • can measure length and add radius of bob
  • angle between string and downwards vertical at maximum should be less than 15 degrees
  • can use motions tracker and data logger for greater accuracy